--Rigid Object Instance Non-uniform scaling

[jturner65]

Motivation and Context

This PR adds SceneObjectInstance support of non-uniform scaling. Coupled with the existing online support of modifying scale via setting stage or object config attributes, non-uniform scaling capabilities can be provided to the user. Note : this scaling is only available before instantiation - once an object is instantiated, the scale is set and unmodifiable (as is the existing paradigm for scale).

Please also see this PR for an alternative, online approach to nonuniform scaling.

How Has This Been Tested

Existing c++ and python tests pass. C++ tests added to verify appropriate load from json and save to json file for new fields.

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have completed my CLA (see CONTRIBUTING)
• I have added tests to cover my changes.
• All new and existing tests passed.

[aclegg3]

LGTM, thanks.